Apparatus and method for forming multiple plugs in a wellbore

Abstract

An apparatus and method for forming plugs in a wellbore, according to which a first volume of slurry is introduced into a work string in a wellbore so that it flows through the work string and discharges before hardening to form a plug. A second volume of slurry is also introduced into the work string so that it flows through the work string and discharges before hardening to form an additional plug.

1. An apparatus for forming multiple plugs in a wellbore, comprising:
 a first tubing section having an upper end and a lower end; 
 a first tool located below the first tubing section and connected in fluid communication with the lower end of the first tubing section, the first tool comprising:
 at least one body member having a bore for permitting a first volume of fluid to pass into the bore and discharge from an end of the bore into the wellbore; 
 at least one port in the body member that communicates with the bore for permitting a second volume of fluid to pass into the bore and discharge from the at least one port into the wellbore; and 
 means for normally covering the at least one port to permit the first volume of fluid to discharge from the end of the bore into the wellbore, wherein the means is adapted to uncover the at least one port to permit the second volume of fluid to discharge from the at least one port into the wellbore; and 
 
 a second tool located above the first tool and connected in fluid communication with the upper end of the first tubing section, the second tool comprising:
 an upper body member; 
 a lower body member coupled to the upper body member; and 
 means for decoupling the upper and lower body members to permit the upper body member, and any tubing sections above the upper body member, to be removed from the wellbore. 
 
 
   
   
     2. The apparatus of  claim 1 , wherein at least one of the first volume of fluid and the second volume of fluid is a slurry that hardens after being discharged into the wellbore. 
   
   
     3. The apparatus of  claim 1 , wherein the first tool extends between the first tubing section and a second tubing section and wherein the first volume of fluid is a slurry that hardens after being discharged into the wellbore below the second tubing section that extends below the first tool. 
   
   
     4. The apparatus of  claim 1 , wherein a first plug is formed in the wellbore by the first volume of fluid and a second plug that extends in an axially spaced relation to the first plug is formed in the wellbore by the second volume of fluid. 
   
   
     5. The apparatus of  claim 1 , wherein the second volume of fluid discharges into the wellbore at an elevation in the wellbore that is above the first volume of fluid in the wellbore. 
   
   
     6. The apparatus of  claim 1 , wherein the second volume of fluid is a slurry that hardens, around the lower body member of the second tool. 
   
   
     7. The apparatus of  claim 1 , wherein the first tool is connected in fluid communication with and is above a second tubing section and wherein the second tool is connected in fluid communication with and is between the first tubing section and a third tubing section. 
   
   
     8. The apparatus according to  claim 1 , further comprising:
 a first ball configured to interact with the means for normally covering the at least one port; and 
 a second ball configured to interact with the means for decoupling the upper and lower body members. 
 
   
   
     9. The apparatus according to  claim 8 , wherein the first ball is smaller than the second ball. 
   
   
     10. A method for forming multiple plugs in a wellbore, comprising:
 connecting a first tool in a work string; 
 introducing a first volume of slurry into the work string so that it flows through the work string and discharges from a lower portion of the work string that is located below the first tool; 
 terminating the step of introducing the first volume of slurry; 
 allowing the first volume of slurry to harden; 
 opening at least one normally-closed port that extends through a wall of the first tool; 
 introducing a second volume of slurry into the work string so that it flows through the open at least one port and discharges from the at least one port; 
 terminating the step of introducing the second volume of slurry; 
 allowing the second volume of slurry to harden; 
 decoupling an upper portion of the work string that is located above the first tool from the first tool; and 
 removing the upper portion of the work string from the wellbore. 
 
   
   
     11. The method of  claim 10 , wherein a continuous bore is formed through the work string and the first tool so that the first volume of slurry normally passes through the bore before discharging into the wellbore. 
   
   
     12. The method of  claim 11 , wherein the slurry hardens after being discharged into the wellbore so that a first plug is formed in the wellbore by the hardened first volume of slurry, and a second plug is formed in the wellbore by the hardened second volume of slurry. 
   
   
     13. The method of  claim 12 , wherein the second volume of slurry discharges into the wellbore at an elevation in the wellbore that is above the elevation where the first volume of slurry discharges so that the second plug extends above the first plug. 
   
   
     14. The method of  claim 10 , wherein the step of opening comprises moving a sleeve in the first tool to uncover the at least one port. 
   
   
     15. The method of  claim 14 , wherein the at least one port is formed through the at least one body member of the first tool and is normally covered by the sleeve, and wherein the at least one port is uncovered in response to the movement of the sleeve. 
   
   
     16. The method of  claim 10 , wherein:
 the first tool extends between an upper tubing section above the first tool and a lower tubing section below the first tool; 
 a first portion of the first volume of slurry discharges into the wellbore below the lower tubing section; and 
 the second volume of slurry discharges into an annulus between the wellbore and the first tool. 
 
   
   
     17. The method of  claim 10 , wherein the step of removing the upper portion of the work string comprises decoupling an upper portion of a second tool from a lower portion of the second tool to permit the upper portion of the second tool and a portion of the work string that extends above the upper portion of the second tool, to be removed from the wellbore. 
   
   
     18. The method of  claim 17 , wherein the first volume of slurry hardens around the lower portion of the first tool and the second volume of slurry hardens around the lower portion of the second tool. 
   
   
     19. The method of  claim 10 , wherein the first volume of slurry is less than a volume of fluid the wellbore can withstand. 
   
   
     20. The method of  claim 19 , wherein the first tool distributes the first volume of slurry up to about the location of the at least one port. 
   
   
     21. The method of  claim 10 , wherein the second volume of slurry is less than a volume of fluid the wellbore can withstand. 
   
   
     22. The method of  claim 21 , wherein the first tool distributes the second volume of slurry to an elevation within the wellbore higher than the elevation of the first tool.